Stress Dependence of Ultrasonic Velocity in Unidirectional Graphite/epoxy Composites for Longitudinal Waves Propagating along the Direction of Stress Introduction

One effect of nonlinear elasticity on elastic wave propagation is that the velocity of the elastic wave is a function of the applied stress on the material. This effect has been used to characterize the nonlinear elastic properties of numerous materials and is also important in attempts to nondestructively characterize residual and applied stress in materials. In addition, investigations have established a possible correlation between the nonlinear elastic properties and ultimate strength in conventional materials such as aluminum [1] and carbon steel [2].